8,842 research outputs found
Convexity in a masure
Masures are generalizations of Bruhat-Tits buildings. They were introduced to
study Kac-Moody groups over ultrametric fields, which generalize reductive
groups over the same fields. If A and A are two apartments in a building, their
intersection is convex (as a subset of the finite dimensional affine space A)
and there exists an isomorphism from A to A fixing this intersection. We study
this question for masures and prove that the analogous statement is true in
some particular cases. We deduce a new axiomatic of masures, simpler than the
one given by Rousseau
Gindikin-Karpelevich finiteness for Kac-Moody groups over local fields
In this paper, we prove some finiteness results about split Kac-Moody groups
over local non-archimedean fields. Our results generalize those of "An affine
Gindikin-Karpelevich formula" by Alexander Braverman, Howard Garland, David
Kazhdan and Manish Patnaik. We do not require our groups to be affine. We use
the hovel I associated to this situation, which is the analogue of the
Bruhat-Tits building for a reductive group.Comment: International Mathematics Research Notices, Oxford University Press
(OUP), 201
Completed Iwahori-Hecke algebras and parahorical Hecke algebras for Kac-Moody groups over local fields
Let G be a split Kac-Moody group over a non-archimedean local field. We
define a completion of the Iwahori-Hecke algebra of G. We determine its center
and prove that it is isomorphic to the spherical Hecke algebra of G using the
Satake isomorphism. This is thus similar to the situation of reductive groups.
Our main tool is the masure I associated to this setting, which is the analogue
of the Bruhat-Tits building for reductive groups. Then, for each special and
spherical facet F, we associate a Hecke algebra. In the Kac-Moody setting, this
construction was known only for the spherical subgroup and for the Iwahori
subgroup
Modeling the dynamical interaction between epidemics on overlay networks
Epidemics seldom occur as isolated phenomena. Typically, two or more viral
agents spread within the same host population and may interact dynamically with
each other. We present a general model where two viral agents interact via an
immunity mechanism as they propagate simultaneously on two networks connecting
the same set of nodes. Exploiting a correspondence between the propagation
dynamics and a dynamical process performing progressive network generation, we
develop an analytic approach that accurately captures the dynamical interaction
between epidemics on overlay networks. The formalism allows for overlay
networks with arbitrary joint degree distribution and overlap. To illustrate
the versatility of our approach, we consider a hypothetical delayed
intervention scenario in which an immunizing agent is disseminated in a host
population to hinder the propagation of an undesirable agent (e.g. the spread
of preventive information in the context of an emerging infectious disease).Comment: Accepted for publication in Phys. Rev. E. 15 pages, 7 figure
The Use of Arrest Records In Pre-Employment Screening In Franklin County, Ohio
Researchers reviewed the legality of employers using arrest records without convictions in pre-employment screenings; conducted surveys and focus groups to learn about pre-employment screening practices in Franklin County, OH; and studied arrest record data to determine whether black males in the region were more likely than others to be arrested and not subsequently convicted
Black-hole kicks from numerical-relativity surrogate models
Binary black holes radiate linear momentum in gravitational waves as they
merge. Recoils imparted to the black-hole remnant can reach thousands of km/s,
thus ejecting black holes from their host galaxies. We exploit recent advances
in gravitational waveform modeling to quickly and reliably extract recoils
imparted to generic, precessing, black hole binaries. Our procedure uses a
numerical-relativity surrogate model to obtain the gravitational waveform given
a set of binary parameters, then from this waveform we directly integrate the
gravitational-wave linear momentum flux. This entirely bypasses the need of
fitting formulae which are typically used to model black-hole recoils in
astrophysical contexts. We provide a thorough exploration of the black-hole
kick phenomenology in the parameter space, summarizing and extending previous
numerical results on the topic. Our extraction procedure is made publicly
available as a module for the Python programming language named SURRKICK. Kick
evaluations take ~0.1s on a standard off-the-shelf machine, thus making our
code ideal to be ported to large-scale astrophysical studies.Comment: More: https://davidegerosa.com/surrkick - Source:
https://github.com/dgerosa/surrkick - pypi:
https://pypi.python.org/pypi/surrkick - Published in PR
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